Genetic Analysis of Familial Keloids

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Bethesda,
Maryland20892

Purpose:

The purpose of this study is to identify the gene or genes responsible for keloid formation.
Keloids are raised scars on the skin that form after a minor injury. A tendency to develop
keloids often runs in families, suggesting a possible genetic basis.
People who have had a classic (butterfly-shaped or wound-overflowing) keloid for at least one
year may be eligible for this study. In addition to these probands (original participants),
family members over 12 years of age who have either classic or non-classic keloids and those
18 years of age or older without keloids may participate.
Probands and family members with keloids will have a medical history focusing on skin
problems particularly keloids and a skin examination. In some cases, with the subject s
permission, photos of the keloids will be taken. All participants will have 35 milliliters
(about 2 tablespoons) of blood drawn for DNA (genetic) testing and for measurement of blood
proteins, including cytokines, which can affect other tissues and cause scarring. Part of the
blood sample will be used for additional genetic studies unrelated to keloids. The samples
will be coded for confidentiality.

Study summary:

Keloids represent a pathologic fibrosis which occurs in the skin after trauma and which grow
beyond the boundaries of injury. Keloids occur in people of all racial backgrounds; however,
individuals of African descent are more susceptible to the disease. A familial disposition to
keloid formation has long been recognized, but the genetic basis for this racial and familial
predisposition has not been identified. We hypothesize that the increased risk is a direct
result of one or more disease susceptibility genes. We will pursue two approaches, which are
presented as two study modules. In module 1, we will carry out a family study. We will
identify affected pedigrees, each containing at least 3 individuals with keloids. Blood will
be obtained and Epstein Barr virus-transformed permanent B cell lines will be established. We
anticipate taking two analytic strategies. We will use candidate gene analysis, focusing
initially on the CBP and TGF1B genes and a recently identified locus on chromosome 14, and we
will use genome-wide markers to identify possible disease gene loci. In module 2, we will
perform a genome scan to address the hypothesis that one or more African origin genetic
variants account for the excess prevalence of keloids among African Americans. We will carry
out a mapping by admixture linkage disequilibrium (MALD) scan, in order to find genetic
regions where differences in the distribution of particular tagging single nucleotide
polymorphisms (SNPs) between keloid cases and controls indicate excess African ancestry.
Further analysis of these loci will be carried out to identify the causative genetic
variants.

Criteria:

- INCLUSION CRITERIA:
1. Proband: must have a butterfly-shaped or wound-overflowing keloid, present for at
least one year (this description represents classic keloid, and avoids
hypertrophic scar)
2. Affected family members: all family members of the proband who have either
classic keloids, as described above, or non-classic keloids, such as ball
shaped-keloids on the ear.
3. Unaffected family members: all family members who lack keloids.
4. Impaired subjects for whom a legal guardian provides consent.
5. Pregnant women.
EXCLSUION CIRTERIA:
1. Subjects who are unwilling or unable to give informed consent or assent.
2. Impaired individuals from whom it not possible to obtained parental consent (minors)
or guardian consent (adults).
3. Keloid patients who have <3 relatives with keoids.